Tuesday, December 12, 2006

Arthropod diversity as a criterion for selection of hedgerow species within the concept of landscape design for ecological production

Rebecca Lee, rebeccal@asocolflores.org1, Jose Ricardo Cure, jrcure@umng.edu.co2, and Maria Mercedes Perez2. (1) Ceniflores, Carrera 9 A, No. 90-53, Bogota, D.C, Colombia, (2) Nueva Granada Military University, Department of Applied Biology, Cr 11 No. 101-80, Bogota, Colombia

In a first phase, insects and spider mites were collected from six native tree species used as hedgerows on flower farms in two locations on the Bogotá Plateau (Colombia). Arthropods were separated by morphospecies, their feeding habit was determined, and species dominance established. Arthropod richness was reflected by the 141 species collected, the number of taxonomic categories found (12 orders and 75 families), the average of 75 species associated with each tree species, and the different trophic levels represented. Of the species collected, 34% were herbivore, 27% visitors, 21% parasitoids, 9% predators and 9% saprophagous. Six species were of economic importance in floriculture; however, for each of them at least one natural enemy was also found. In a second phase, additional native trees, as well fruit trees and herbs, were included from a vegetable producing area. The resulting list of arthropod species, particularly the parasitoids and predators of common crop pests, was analysed for plant species preference. An ecological infrastructure index was then used to design a network of hedgerows for the municipality based on existing vegetation and a calculation of missing linear meters. The selection of plant species was recommended on the basis of their capacity as hosts for naturally occurring biological control agents, as well as physiological aspects such as height and their use as a human food source.